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The Feelings of Fish

photograph of bass fish underwater

“It’s okay to eat fish, ‘cause they don’t have any feelings.”

So sang Nirvana frontman Kurt Cobain in the haunting “Something in the Way.” Here’s the problem, however: according to recent research, fish do have feelings – and this stands to create all sorts of concerns for how humans treat these animals.

A study published just last month shows that fish are able to pass the Mirror Test – being capable of recognizing themselves in mirror reflections and photographs. This test is an important indicator of an advanced level of cognitive capabilities in both human and non-human animals, and sees fish join an elite club previously only occupied by humans, dolphins, elephants, and some great apes. This latest study joins a mounting body of research showing that fish do, in fact, have a much higher level of cognition than we previously thought. For one, they don’t have a three-second memory. In fact, they tend to remember things for a period of about five months. Further, a 2019 study showed that fish experience pain in much the same way as humans; exhibiting accelerated ventilation rates and showing an ability to avoid pain-inducing stimuli. They even rub areas of their bodies that have suffered pain – much as we do a stubbed toe.

So what do these latest developments mean for the ethical treatment of fish? Why might features such as self-recognition and the ability to feel pain be relevant in considering what we can permissibly do to fish?

A few months ago, I considered a similar problem relating to our treatment of insects. Recent research had suggested that – contrary to our traditional understanding – insects might be capable of experiencing pain. I explained how the ability to feel pain (and its corollary, pleasure) is, for some ethicists, all that is required for a living being to have interests. How so? Well, if something can experience pain, then it has an interest in avoiding pain. In fact, the fish in the study cited above showed precisely this behavior – avoiding areas of their tanks where they received electric shocks, even where those areas were previously associated with feeding.

Suppose, then, that I want to go for a spot of recreational “catch-and-release” fishing. Is it wrong for me to do so?

One starting point might be to note that even if fish can experience pain (and have a corresponding interest in avoiding pain) the amount of suffering caused by a single barbless hook through the mouth is relatively small. Suppose that, for a fish, this experience is roughly about as painful as it would be for a human to be pierced in the back of the hand with a sharp needle. This might seem acceptable. But would we think it morally permissible for someone to go around stabbing others in this way for purely recreational purposes? If our answer is “no,” then we have a problem.

The reason why this is problematic comes down to the principle of equality.

Previously, I discussed how when we talk of the equality of humans, we aren’t generally claiming that all humans are equal, nor that they should be equal. Rather, equality is taken as a prescription that the interests of all humans should be given equal consideration. This is the principle that underpins the wrongness of sexism, racism, and other forms of bigotry.  It’s why it’s morally impermissible to prioritize one person’s interests in, say, being given a promotion based merely on their gender or skin color. Instead, the interests of these individuals need to be considered equally.

So, if two individuals have an interest in not experiencing pain, then those interests have to be treated equally. And if we believe that inflicting X amount of pain on one individual is morally impermissible, then we must believe that inflicting that same amount of pain on another individual is just as wrong. Further, we’re not permitted to make a distinction based purely on the species of the individual. Why? Because doing so would violate the principle of equality in the same way that sexism or racism does. In this case, however, it would be speciesist.

As with the ethical treatment of insects, we might consider discounting – or disqualifying altogether – the suffering of fish on the basis that they aren’t as intelligent as humans. But this contravenes the very same principle of equality.

Consider how we think about humans: Do we believe it is more morally permissible to cause pain and suffering to those who are less intelligent? Do we allow harm to very young children on the basis that they do not have the same cognitive faculties as fully developed adults?

Clearly not. So we must take the same approach to animals like fish.

Given all of this, it seems that if fish do truly experience pain in a way that is similar to humans, then something like recreational catch-and-release fishing becomes morally impermissible (assuming, of course, that we’re not willing to endorse harming humans in the same way for fun). But what if the harm caused to these fish wasn’t merely recreational, but was instead done for survival? Would it be permissible for us to catch-and-kill fish for this purpose?

This is where the waters become a little murky. Peter Singer – the proponent of the approach taken above – is a Utilitarian, meaning that he believes the morally right thing to do is that which maximizes pleasure (or minimizes pain). Thus, if a family was in desperate need of sustenance, the pain and suffering inflicted on a fish by catching and killing it for dinner might be outweighed by the good of the family’s continued survival. But here’s the thing: for many of us, this will never be the case. Most of us in developed nations have ample sources of sustenance that do not require the suffering of fish – or any animal for that matter. This is precisely why Singer argues so forcefully in favor of veganism.

Ultimately, however, all of this comes back to the question of whether fish do truly experience pain in a morally relevant way. And while some will take these latest studies as clear evidence that they do, others will remain skeptical that the kind of thing being experienced by fish (and insects and other animals) is fundamentally different to that experienced by humans. And that might turn out to be the case. I have, however, previously noted our very poor track record of understanding pain in other living beings (even infant humans). Given this, it would seem that caution is in order – and that the best approach might be to refrain from recreationally harming an animal that may turn out to experience pain in a way similar to humans.

Passing the Mirror Test and the Wrong of Pain

Photograph of a striped fish called a cleaner wrasse in front of coral with another different species of fish in view behind

In mid-February, scientists announced progress in developing an understanding of consciousness. An international team collaborating in four countries discovered patterns of brain activity that coincide with awareness. Consciousness has long been a mystery, and there are many reasons to explore and figure it out. It seems like creatures who have some form of consciousness make up a special club, experiencing the world with more layers, perhaps with more complex agency, perhaps uniquely making up the moral community.

These potential steps forward in understanding our brain-based and embodied consciousness come alongside a purported broadening of the group of animals that scientists claim pass the mirror-test for self-awareness. As we try to put our fingers on what it means to be conscious, in the last century Western philosophers have become open to the idea that there is a rich arena of animal perspectives alongside our own. The variety of ways that we can imagine experiencing the world has grown with our study of human and non-human animal experiences. This has interesting implications for who we include in our understanding of our moral community and how we understand the ways we can harm these members.

Though it is pretty intuitive that causing harm is bad, explaining why can be notoriously difficult. One route is appealing to the negative experience of harm – primarily how bad experiencing pain is. This focus unites human and non-human animals that can feel pain into one morally relevant domain. If what is bad about causing harm is that it brings about this negative experience of pain, then we need to identify the sorts of creatures that experience pain and avoid bringing about those states without outweighing reasons. Thus, consciousness will be morally relevant insofar as it delineates those creatures that are in some way aware of their experiences.

There are two responses to this line of thinking. One direction argues that this grounding of the badness of causing harm is too narrow: there are harms that we don’t experience, so this understanding misses morally relevant behaviors. Another direction claims that this line of thinking is too broad: not all pain is morally relevant.

Consider the (false) common conception of the perspective of a goldfish, where their understanding of the world resets every 10 seconds. Would causing pain to a creature who would very quickly have no memory of it have the same moral relevance as causing pain to something that would incorporate it into its understanding of the world indefinitely? Take the faux-goldfish example to its conceptual extreme and imagine a creature that has the experience of pleasure and pain, but only has instantaneous experiences – it lacks memory. Presumably, it wouldn’t matter to the creature a moment after it felt pain that it felt pain a moment ago because it had no residual impact from the experience (unless prolonged damage was done). If you share this intuition, then something more than the mere experience of pain is involved in the morality of causing harm.  

The way to make pain morally relevant is to focus on the perspective of the creature experiencing the pain – that there is such a perspective extended in time that experiencing the pain will impact. We can imagine the fear of a non-human animal in unfamiliar circumstances and consider the anxiety that may develop over time if it is continuously exposed to such circumstances. Such creatures have a sort of “self,” in the sense that their experience of the world develops their mode of interacting with the world and understanding of the world over time.

There is an even more advanced way of being a creature in the world beyond stringing experiences together in order to have a perspective extended in time: a creature can be aware that it has such a perspective by being aware that it is a self.

A key experiment to check the development of a self-concept is the mirror-test, where an animal has a mark placed on their body that they cannot see by moving their eyes. If, when they see the mark on a body in a mirror, they come to the conclusion that their own body has the mark, then they “pass” the mirror test because in order to come to such a conclusion the animal must use an implicit premise that they are a creature that could be so marked. The mirror-test is thus meant to indicate that an animal has self-awareness. It relies on a variety of competencies (vision and figuring out how mirrors work, for instance), but has long been thought to be sufficient for indicating that a creature is aware that it exists in the world.

Humans don’t pass the mirror test until they are toddlers, and only some primates also are able to pass the test, along with sundry birds and other mammals. However, this past year a tiny fish – the cleaner wrasse – seemed to pass the test. It is a social animal, considered to be relatively cognitively advanced, but the scientists who advocated for the results of the mirror-test suggest that while yes, this is a smart and advanced fish, this may not mean that it is self-aware. The success of the small fish has raised issues in how we test for morally relevant milestones in non-human animals.

One interesting facet of the mirror test is that animals that perform well are social, which is often a morally relevant trait. If morality is a matter of treated others with the sort of deference they are due, then a sort of sociality for members of the moral domain makes some sense.

In defining our moral community, most theorists include some non-human animals, and most consider it relevant to identify the way creatures experience the world. These latest advances in mapping consciousness and advancing our interpretation of self-awareness tests will help us understand the spectrum of relationships possible in the animal world. 

This article has a set of discussion questions tailored for classroom use. Click here to download them. To see a full list of our discussion questions, check out the Educational Resources page.